"We knew he was crazy, but not like this," said Angela Holloway, who was married to the gunman Keith Thomas Kinnunen for eight years before they divorced in 2010. "I don't wish this on anybody. I feel sorry for the victims. I really do."

"Mentally, I know he was mentally ill," she told NBC Dallas-Fort Worth in an interview Monday. Holloway said she last spoke with Kinnunen, who had an extensive criminal record spanning multiple states, about three years ago. "He just wasn't in his right mind.

"I didn't know how to go about talking to him about it," Holloway said, adding that he suffered from a drug habit.

"He's gone," Holloway said. "There's nothing I can do about it, but I'm glad it got stopped."

Keith Kinnunen, in an undated booking photo, was identified as the shooting suspect at a church in White Settlement, Texas.Tarrant County Sheriff's Office / Reuters file

The church had previously provided Kinnunen, 43, with food on multiple occasions, but when he asked for money he wasn't given any, according to Britt Farmer, a senior minister for the congregation.

But on Sunday, he wore a wig and fake beard and wasn't recognized. Some church members were spooked by the strange-looking man, while Wallace's daughter said she intended to welcome the person she thought was a visitor.

Matthew DeSarno, the special agent in charge of the FBI's Dallas field office, said Kinnunen was "relatively transient," but had roots in the area.

After his divorce from Holloway, he tried to reconnect with his first wife, Cindy Glasgow-Voegel, who subsequently filed a protective order against him in Grady County, Oklahoma, in 2012, NBC Dallas-Fort Worth reported.

In a statement at the time, she wrote, "Keith is a violent, paranoid person with a long line of assault and batteries with and without firearms. He is a religious fanatic, says he's battling a demon ... He is not nice to anyone."

She wrote that Kinnunen had showed up without notice in 2011, asking to see his teenage son, who was "terrified of him."

According to an arrest affidavit, the son told police in 2011 that he was with Kinnunen when he set a cotton field on fire using lamp oil, tampons and a lighter. The son also said Kinnunen liked to play "fire football," in which he would soak the ball in flammable liquid, light it on fire and toss it back and forth with the teen.

Kinnunen was also charged in Grady County, Oklahoma, with aggravated assault and battery in 2011.

In Tarrant County, Texas, he had been charged with aggravated assault with a deadly weapon in 2009 and theft of property in 2013. He was also arrested in 2009 and 2015 in River Oaks.

More recently, he was arrested in 2016 for possession of an illegal weapon in Linden, New Jersey, according to NBC New York.

The FBI is working to identify Kinnunen's motive. Investigators began searching his home after the shooting Sunday.